固定表达，在语境中理解。

在移动中；忙碌奔波

With the new rail line open, residents are on the move between the two towns all day.

一方面（常与 on the other hand 对应）

On the one hand, the old bridge is charming; on the other hand, it is too narrow for buses.

大约；数量级为

Replacing the roof will cost on the order of two hundred thousand dollars, not twenty thousand.

另一方面；从另一方面看；另一方面；换个角度说；另一方面；不过

On the other hand, strong neurite-promoters such as laminin, are also present in peripheral nerves.

在另一边；另一方面

The picnic area is on the other side of the hill, just beyond the wooden footbridge.

在……的另一边；在……的另一边；在……对面

There's a small pharmacy on the other side of the park, across from the school.

在外面；外侧；表面上

The bread should be golden on the outside and soft in the middle.

由……一方；在……方面

The data error was an honest mistake on the part of the contractor, but it still delayed the review.

在通电话；在打电话；通过电话

She was on the phone with her doctor when the delivery driver arrived.

从好的一面看；值得庆幸的是

The flight was delayed by an hour, but on the plus side, the airline provided dinner for everyone.

成为某种行为或影响的承受方

After years of assigning last-minute tasks to others, the manager was finally on the receiving end of the same treatment.

正式记录在案；可公开引用地

The mayor discussed the budget on the record after the council meeting.

在右边；在右侧

Keep your passport in the pocket on the right of your backpack.

方向正确；做法对路

Your first draft is on the right track; adding one clear example will strengthen it.

在上升；不断增加

Demand for evening classes is on the rise as more workers change shifts.

在路上；旅途中

We've been on the road since dawn, so let's stop for lunch before we get tired.

在逃；奔波不停

The escaped horse was on the run until a stablehand guided it into a quiet field.

在同一队；目标一致

Even when we disagree about the schedule, we're on the same team.

在现场；赶到现场

Fire crews were on the scene within minutes and quickly secured the intersection.

被搁置；暂时不推进

The renovation plan sat on the shelf until the grant came through.

另附；作为配菜；另外；兼职地；作为副业；另外；在一旁；另附；作为副业

The bakery serves the soup with a small salad on the side.

当场；立即；当场；就地（立即在现场进行）

The mechanic found the fault and fixed it on the spot, so we were back on the road within an hour.

一时兴起；未经事先计划地

On the spur of the moment, we booked a table near the harbor and watched the sunset.

在街上；沿街

A street musician was playing a violin on the street outside the theater.

表面上；乍看之下

On the surface, the two plans look similar, but their long-term costs differ sharply.

摆在桌上；提出来供讨论；摆上桌面讨论；正在考虑之中

The council put three designs on the table before voting on the new park entrance.

濒临；即将

After three days without power, the remote station was on the verge of running out of fuel.

即将；濒临（某事发生）；濒临；即将；正处于……边缘

The city seemed on the verge of slipping into Puget Sound and disappearing forever.

在路上；途中；即将到来；在路上；正在前往；在途中；在路上

I picked up fresh bread on the way home because the bakery was closing early for the holiday.

在去……的路上；即将达到

On the way to the clinic, we stopped to help a cyclist whose chain had slipped off.

总的来说；总体上；总的来说；整体上

On the whole, I like the new place; it's just a bit far from work.

他们自己；独立地

The interns completed the inventory on their own after the supervisor explained the system.

准时；按时；准时；按预定时间

The last shuttle arrived on time, so the concertgoers reached the venue before the doors opened.

除了……之外；在……上面；在……上面；覆盖在……之上；在……上面；位于……顶部

On top of her regular duties, Nina organized the weekend fundraiser and arranged rides for the volunteers.

除此之外；而且

The bus was late, and on top of that, I had left my lunch on the kitchen counter.

在度假；休假中

Our manager is on vacation this week, so urgent requests should go to her assistant.

挂在心上；让你惦记

You seem quiet this evening; is something on your mind?

独自；靠自己

You can explore the museum on your own after the guided tour ends, as long as you return before closing.

站在你这边；支持你

Even if the committee disagrees, you still have someone on your side.

在你去……的路上；顺便

Could you pick up a carton of milk on your way home from the evening class?

再次；又一次；再一次；又一次

The board once again postponed the vote while it reviewed the new evidence.

彻底地；一劳永逸地

This new form of economic management changed the landscape of the Lake District once and for all.

极少；千载难逢地

We only order dessert once in a blue moon, so tonight feels like a treat.

偶尔；时不时；偶尔；有时

The adviser checks the figures once in a while to catch unusual changes.

再一次；再说一遍

Could you read the address once more? I want to confirm the apartment number.

一两次；偶尔

I've spoken to the new manager once or twice, but I do not know her well yet.

从前；很久以前（故事开头用语）

Once upon a time, a fox guarded the only bridge across the valley.

彼此；互相

The teammates encouraged one another through the final stretch of the relay.

一次一个；逐个地

The technician checked each connection one at a time so she could identify the faulty cable.

一个接一个地；逐一地

The technician tested the backup batteries one by one before reconnecting the control panel.